imap: fix docs for rename-folder.
imap: fix docs for rename-folder.

bjourne/factor,slavapestov/factor,slavapestov/factor,AlexIljin/factor,bjourne/factor,bpollack/factor,mrjbq7/factor,bpollack/factor,mrjbq7/factor,sarvex/factor-lang,dch/factor,slavapestov/factor,dch/factor,AlexIljin/factor,bpollack/factor,mrjbq7/factor,nicolas-p/factor,tgunr/factor,nicolas-p/factor,dch/factor,mrjbq7/factor,nicolas-p/factor,AlexIljin/factor,bjourne/factor,sarvex/factor-lang,nicolas-p/factor,dch/factor,factor/factor,tgunr/factor,bjourne/factor,factor/factor,bpollack/factor,bjourne/factor,sarvex/factor-lang,dch/factor,bjourne/factor,bjourne/factor,factor/factor,AlexIljin/factor,sarvex/factor-lang,mrjbq7/factor,AlexIljin/factor,sarvex/factor-lang,tgunr/factor,slavapestov/factor,bpollack/factor,factor/factor,tgunr/factor,bpollack/factor,dch/factor,AlexIljin/factor,bpollack/factor,slavapestov/factor,tgunr/factor,nicolas-p/factor,AlexIljin/factor,mrjbq7/factor,sarvex/factor-lang,slavapestov/factor,slavapestov/factor,tgunr/factor,factor/factor,nicolas-p/factor,sarvex/factor-lang,factor/factor,nicolas-p/factor